by Jim Morrison
If you are having a problem with your Tiger’s clutch not fully disengaging, one potential solution is the installation of a clutch master cylinder with a 0.750-inch bore to replace the stock unit (having a bore of 0.625-inches). This will provide greater movement of the clutch arm for the same pedal movement. As the volume of hydraulic fluid displaced (for the same pedal movement) is a function of the square of the bore diameter, the increase in bore will result in a 44% increase in clutch arm movement.
But all this does not come without a trade off: clutch pedal effort is also increased by 44%. I have made this change to my car with good results, previously having had some trouble with a dragging clutch. The pedal effort is high but not unbearable (with a 2200 lb. performance pressure plate). The larger bore clutch master cylinder can be purchased through a Sunbeam parts supplier. Be sure to specify a bore size larger than 0.625″. 0.700″ and 0.750″ are the next two popular sizes.
Comments (3)
Do they make a smaller bore clutch master?
I rebuilt a TR4 .75 clutch m/c and replaced the original 5/8 m/c in my Tiger with good results. I’ll get used to the heavy pedal. Your article is right on.
Did you have any issues with the clutch arm traveling too far? If so, how did you address that? Thanks, Jeff Lemon